Vacuum switch and actuator assembly



Sept. 8, 1964 J. E. JENNINGS VACUUM SWITCH AND ACTUATOR ASSEMBLY Filed July 16, 1962 v IN VEN TOR.

lI/IS 447' 7' ORA/E Y United States Patent Office 3,148,259 VACUUM SWITQH AND ACTUATGR ASSEMBLY Jo Emmett Jennings, Watsonville, Caiifi, assignor t Jennings Radio Manufacturing Corporation, San Jose, Calif., a corporation of Delaware Filed July 16, 1962, Ser. No. 269,846 7 Claims. (Cl. 2{l-144) This invention relates to vacuum switches for use in high power and high frequency circuits. More particularly the invention is directed to means for mounting a vacuum switch on an actuator or operating device and at the same time effectively insulating the actuator from the switch.

In high power, high frequency vacuum switches, it becomes increasingly diflicult to insulate the switch, the terminals of which are at high potential, from the switch actuating means to which the switch is mechanically connected, without employing unduly large bulky structures. The most effective dielectric materials are usually diflicult to machine and have a low tensile strength in comparison with their compressive strength. This characteristic of low tensile strength makes such materials undesirable for use in connecting the actuator to the switch despite the fact that their dielectric qualities are extremely desirable.

It is an important object of this invention to provide an assembly of switch and switch actuator means which incorporates the use of a high quality dielectric material for insulating the switch from the actuating means, and at the same time provides an arrangement wherein said dielectric material is always maintained in compression and not in tension, thus increasing its mechanical eflectiveness and durability.

It is another object of the invention to provide a normally open vacuum switch in which the connection between the switch and the actuating means is variable to permit adjustment of the gap between the switch contacts.

Still another object of the invention is the provision of a vacuum switch and actuating means therefor which may be easily assembled and disassembled.

Other objects and advantages of the invention will become apparent from the following description and the accompanying drawings, wherein:

FIG. 1 is a side elevation of my vacuum switch and actuator assembly, partly broken away to show internal details. The plane of section of the central flanges is indicated by the line 1-1 of FIG. 2.

FIG. 2 is a cross sectional view taken in a plane represented by lines 2-2 in FIG. 1.

In terms of broad inclusion my switch and operator assemblies comprise a pair of glass or ceramic envelopes; one vacuumized and containing the sub-assembly of fixed and mobile switch contacts, with a switch operating stem functioning thru sealing bellows. The other envelope remains at atmospheric pressure and contains the operator comprising a dielectric rod with adjustable coupling means at one end for connection to the free end of the switch stem, and means at the other end for connection to the armature of a solenoid. Spring means are interposed between the dielectric rod and the end of the envelope to apply pressure against the rod at all times. Current conducting leads are connected to opposite ends of the vacuumized envelope; and a quick-release clamping device is provided for securement of the aligned and adjusted pair of envelopes. The vacuumized envelope with its switch components provides control of power currents, while the envelope at atmospheric pressure with its dielectric shell and dielectric connector rod insures safe operation and handling.

In detail, the invention comprises a switch envelope generally designated 1 which includes a glass or ceramic shell 2 provided at its opposite ends with flared seals 3,148,259 Patented Eaept. 8, 1964 I circuit.

End plate 5 carries a fixed contact support 8 to which is rigidly secured a fixed contact generally designated 9 which includes an annular contact element 10 preferably of tungsten.

The fixed contact element ill cooperates with a mobile contact element 11 carried by a mobile contact generally designated 12 which in turn is rigidly secured to a mobile contact support 13 carried by the inner end of a switch stem 14 which extends outwardly of the envelope 1 thru the end plate 6.

Switch stem 14 is reciprocably supported within a hearing 16 of dielectric material which in turn'is threaded within a central boss 17 formed on end plate 6. At this point it will be noted that upward movement of the switch stems from the position shown in FIG. 1 causes the mobile contact to engage the fixed contact.

In order to hermetically seal the contacts from the atmosphere a bellows 2% is provided and is fixedly secured at its inner end to mobile contact support 13 and at its outer end to the central boss 17 of end plate 6. Although bellows 20 may conduct some current between the mobile contact and the end plate 6, it is preferably to provide a plurality of low resistance high current carrying bonding straps 23 of flexible material for making the connection between the mobile contact 12 and the end plate 6.

The envelope generally designated 30 which contains the actuator means preferably takes a form closely similar to that of the switch envelope 1 in that it includes a glass or ceramic shell 31 provided at one end with a flared seal 32 for connecting the shell to an end plate 33 interfitted with the end plate 6 of the switch envelope. The opposite end of the shell 31 is provided with a similar flared seal 34 conecting the shell with the upper portion 35 of a solenoid generally designated 36.

The outer end of switch stem 14 is threaded for engagement within an internally threaded sleeve 37 which is formed with a radially outwardly extending annular flange 33. A compression spring 49 is interposed between flange 38 and the end plate 33 so as to urge the switch stem 14 outwardly of the switch envelope to separate the contacts 9 and i2. Fixedly secured to the spring retainer flange 38 is a downwardly opening socket member or thimble 41 which is provided with flared end 42 to form a corona shield.

This thimble fits tightly over the upper end of a dielectric connector rod 43. The opposite end of the rod fits snugly within a similar socket or thimble 44 which is also flared outwardly to provide a corona shield 45. The lower thimble 44 is rigidly secured to the upper end of solenoid stem 47 which in turn is provided at its lower end with an armature 48.

At this point it should be noted that although thimbles 4i and 44 are fixedly secured to the flange 38 and stem 47 respectively, it is unnecessary to metalize the connector rod 43 for permanent securement to the thimbles inasmuch as said connector rod is always in compression, so that there is no-tendency for it to pull out of the thimbles. Furthermore, since no tension is applied to the connector rod, high grade dielectric materials may be employed despite the fact that such materials have a low tensile strength.

The armature 43 of the solenoid 36 cooperates with a coil 49 so that when the latter is energized the armature 43 is attracted upwardly to close the switch contacts 9 and 12. Upon deenergization of the solenoid 36 the spring 40 returns the mechanism to the position of FIG. 1, with the solenoid armature in abutment with an annular pad 51 carried by end plate 52 of solenoid.

In order to provide a quick connection of the switch and operator sub-assemblies, a pair of clamps generally designated 56 and 57 (FIG. 2) are provided. These clamps are identical and each is channel shaped in cross section and swingably supported at its end by a pin 58 in the end plate 6. The opposite end of each clamp is provided with a depressed portion 59 which is adapted to cooperate with one of a plurality of indentations hit on the end plate 6 and end plate 33 for yieldably holding the clamp in locked position as seen in FIG. 2. Each clamp includes upper and lower legs 62 and d3 respectively connected together by vertically extending webs 64-.

When it is desired to disconnect the switch assembly from the actuator assembly, it is merely necessary to swing the clamps 56 and 57 outwardly about their pivot pins 58 to elfect separation of the two flanges 6 and 33. After the clamps have been released, the operator envelope may be rotated relative to the switch envelope so as to disconnect the threaded connection between stem 1 and sleeve 37. For smaller sizes and fine easy fitting threads in the sleeve, normal resistance, frictional and otherwise, to rotation of stem 14 and sleeve 37, apart from their enclosing envelopes may be suificient, but I prefer to supply positive means for insuring only axial movement of these parts in their respective envelopes. The stem 14 is fixed for rotation with the switch assembly by a key 65 engaged in a keyway formed in the stem; and the threaded sleeve is fixed for rotation with the actuator assembly by the key 66 engaged in a keyway cut in the bearing 67.

When assembling the units the reverse procedure is followed since it is merely necessary to threadedly connect the stem 14 with the sleeve 37 by rotating the switch and actuator units until end plates 6 and 33 are in engagement. To facilitate this connection end plate 6 of switch unit 1 is provided with a central boss 68 which is received within a complementary recess on end plate 33 of actuator unit 30.

Adjustment of the space between the contacts 9 and I2 is readily effected, when the clamps 56 and 57 are disconnected, by rotating the actuator unit relative to the switch unit so that switch item 14 is moved axially of the sleeve 37 as desired.

It will be noted that in the position of FIG. 1 with the switch open the dielectric connector 43 is in compression in view of the action of spring 4t) tending to urge armature 43 against the pad 51. Similarly, with the contacts closed the coil 4-9 of the solenoid urges the armature 4-8 upwardly again placing the connector rod 43 in compression. At no time is the connector rod required to resist a tensile load.

Atmospheric pressure applied to bellows 2t) will tend to urge the contacts 9 and 12 to a closed position and this atmospheric force is cumulative relative to the force applied by solenoid 36. The compression spring 40 has an opposite elfect and urges the points to an open position. It is therefore a relatively simple matter to design spring 40 to obtain the desired loading and the desired force opening the switch contacts.

The spacing between the solenoid armature 48 and the coil 49 is of course slightly greater than the spacing between the contacts when the latter are open. In this manner a constant force is exerted by energized solenoid 36 urging the contacts to their closed position.

The above specific description of the preferred form of the invention should not be taken to be restrictive thereof as it is obvious that various modifications in design will occur to those skilled in the art without departing from the scope of the following claims.

I claim:

1. The combination of an evacuated envelope having therein a fixed electrode, and a mobile electrode having an axially movable operating stem projecting from the envelope; comprising (I) a conductive end plate on the envelope thru which the operating stem passes and which is electrically connected to the mobile electrode,

(II) means interposed between the stem and end plate for sealing the envelope,

(III) a second envelope open to the atmosphere,

(IV) a second end plate on the second envelope and rotatably interfitting with said conductive end plate,

(V) a housing on which the second envelope is mounted,

(VI) axially reciprocating motor means arranged in the housing,

(VII) a dielectric rod of substantial length connected at one end to the motor means and extending into the second envelope in axial alignment with said operating stem,

(ViII) screw means adjustably connecting the adjacent ends of the dielectric rod and the operating stem,

(lX) a compression spring interposed between the dielectric rod and the second end plate, and

(X) releasable securement means holding the two end plates in rotative adjustment.

2. The combination of claim 1 including:

(XI) a connector lead on each the fixed electrode and on the conductive end plate.

3. The combination of claim 1, in which said housing is formed with an upper portion constituting an end plate having a centrally disposed slide bearing and a lower portion enclosing said motor means which comprises a magnetic coil, an armature, and a stem fixed in the armature and slidably disposed in said bearing.

4. The combination of claim 1 including:

(XI) a corona shield arranged on the dielectric rod.

5. The combination of claim 1 including:

(XI) means fixing the operating stem for rotation with its envelope, and

(XII) means fixing the dielectric rod for rotation with said second envelope.

6. In combination with a vacuumized envelope having a dielectric shell closed at one end by an end plate mounting inside the envelope a fixed electrode and at the other end closed by a conductive end plate having a slide bearing thru which an operating stem extends into the envelope terminating in a mobile electrode electrically connected with the conductive end plate and aligned with the fixed electrode with vacuum sealing means interposed between the operating stem and the conductive end plate, the following:

(I) a second envelope open to the atmosphere and comprising a dielectric shell closed at one end by an end plate rotatably interfitting with the outer face of said conductive end plate and at the opposite end closed by an end plate including a slide bearing and a housing,

(II) a solenoid including an armature and its stem arranged in the housing with the armature stem in said bearing in axial alignment with said operating stem,

(III) a dielectric rod fixed at one end to the armature stem and at the opposite end aligned with and adjacent to said operating stern,

(IV) screw means adjustably connecting the adjacent ends of the dielectric rod and said operating stern,

(V) a compression spring interposed between the dielectric rod and said rotatably interfitting end plate,

(VI) releasable securement means holding the conductive end plate and the end plate interfitting therewith in rotatable adjustment, and

(VII) a connector lead each for the fixed electrode on the outside of the end plate mounting and on the conductive end plate.

7. The combination of claim 6 including:

(VIII) a corona shield element on each end of the dielectric rod.

No references cited. 

1. THE COMBINATION OF AN EVACUATED ENVELOPE HAVING THEREIN A FIXED ELECTRODE, AND A MOBILE ELECTRODE HAVING AN AXIALLY MOVABLE OPERATING STEM PROJECTING FROM THE ENVELOPE; COMPRISING (I) A CONDUCTIVE END PLATE ON THE ENVELOPE THRU WHICH THE OPERATING STEM PASSES AND WHICH IS ELECTRICALLY CONNECTED TO THE MOBILE ELECTRODE, (II) MEANS INTERPOSED BETWEEN THE STEM AND END PLATE FOR SEALING THE ENVELOPE, (III) A SECOND ENVELOPE OPEN TO THE ATMOSPHERE, (IV) A SECOND END PLATE ON THE SECOND ENVELOPE AND ROTATABLY INTERFITTING WITH SAID CONDUCTIVE END PLATE, (V) A HOUSING ON WHICH THE SECOND ENVELOPE IS MOUNTED, (VI) AXIALLY RECIPROCATING MOTOR MEANS ARRANGED IN THE HOUSING, (VII) A DIELECTRIC ROD OF SUBSTANTIAL LENGTH CONNECTED AT ONE END TO THE MOTOR MEANS AND EXTENDING INTO THE SECOND ENVELOPE IN AXIAL ALIGNMENT WITH SAID OPERATING STEM, (VIII) SCREW MEANS ADJUSTABLY CONNECTING THE ADJACENT ENDS OF THE DIELECTRIC ROD AND THE OPERATING STEM, (IX) A COMPRESSION SPRING INTERPOSED BETWEEN THE DIELECTRIC ROD AND THE SECOND END PLATE, AND (X) RELEASABLE SECUREMENT MEANS HOLDING THE TWO END PLATES IN ROTATIVE ADJUSTMENT. 